Different marking systems are previously known, the purpose of which are to provide a marking sign upon the object to be marked. As one such system printing may be mentioned, the drawback of which often is i.a. the poor permanence of the mark on hard surface objects. Further relief letter arrangements and the use of press letters are known, the marking in question usually being temporary to its nature, and the generally poor surface adhesion of the marking constitutes no essential disadvantage. E.g. U.S. Pat. No. 4,159,677 discloses an arrangement, wherein a pattern is pressed into an essentially soft material using embossing bodies fastened on the surface of a cylinder and coated with a separate chromium surface coating.
An object made of metal or the like material having a hard surface can, in a known manner, be marked using cutting or vibrating engraving means or arc machining, in connection with which material is removed from the marked spot. The above mentioned methods make a somewhat permanent mark into the surface of the object, but the complexity especially when the character string i long constitutes a disadvantage. A marking in connection with serial production further requires rather difficult control arrangements.
In marking formable materials it is further known, that the markings may be driven or pressed into the base material using die means shaped as a sign or a sign string. Thus the result will be an imprint in the object surface, the imprint having as such a good permanence and having the shape of the sign or the sign string. The disadvantage of this method has until now been the complex apparatus or alternatively the use of means demanding a great amount of labour as well as the difficulty of producing of special high precision die means. As an example of such means the solutions shown in DE-patent 26 56 615 and EP-application 266 545 may be mentioned.
Especially in connection with hose assemblies or the like there is a demand for making marks into the connector collar, wherein the manufacturer and the manufacturing date are indicated as reference marks using such essentially permanent markings that a recognition later is possible. Such hose assemblies are often manufactured in such a way, that a ductile collar-shaped sleeve means is compressed under high surface pressure around the end of the hose, so that the sleeve means which is deformed under said pressure presses into the hose and locks it against a tubular inner piece. In order to solve i.a. questions of guarantee it has proven necessary, that the collar comprises the above mentioned reference markings, which as such may be scarcely in view, but the permanence of which must be preserved even after rough handling. Further it is sometimes necessary to mark the type, nominal pressure and the like data into the assembly in such a way, that the data is clearly noticeable. For example product liability legislation today imposes very high demands with respect to permanent marking, and for example bar codes which are specific for an object constitute an important part of modern automatic material handling.
Except for individual markings the making of said marks is in practice performed by making a mark in each work piece utilizing a separate marking device or by using letter type dies or the like which are fixed in a press tool or with corresponding loose dies mounted in the tool. When the mark is made using a separate marking device the marking procedure further will require an accessory device and a further phase of work. On the other hand manufacturing loose or fixed letters types arranged in press tools, and especially the replacement of such letter types, is difficult. Fixed letter types or a groove for loose letter types is formed using arc machining, machine cutting or the like method. A separate locking screw is used for locking the loose letter types. Letter types further should be provided in all the different types of tools.
In order to solve these problems the arrangement according to the present invention has been developed, the characteristic features of which appear from the enclosed claims, which are thus incorporated as a part of this specification. In the method according to the invention a separate thin marking device assembly is interposed between the tool and the object to be marked, one or several figure portions of said assembly forming an essentially permanent imprint in the surface of the object. According to the characteristic features of the invention thin die means formed as figures and arranged on a separate, substantially thin holding device are placed between the surfaces of a tool and the object, whereafter the tool in a manner known per se is made to move against the object in such a way, that said die means will be at least partly made to penetrate into the object.